I understand that to use a global variable from a function, you Need to execute the function first:
def f():
global s
s = 'Hello'
f()
print(s)
But how do I use variable s globally in following example:
import sys
from PyQt4.QtGui import QApplication, QMainWindow, QPushButton, QLineEdit, QLabel, QComboBox, QProgressBar, QFileDialog
from PyQt4.QtCore import QSize, pyqtSlot
class App(QMainWindow):
def __init__(self):
super(App, self).__init__()
self.setGeometry(500, 300, 820, 350)
self.setWindowTitle("Widget")
self.initUI()
def initUI(self):
#Buttons
btnposx = 30
btnposy = 50
self.btn4 = QPushButton('GetValue', self)
self.btn4.move(btnposx,btnposy+220)
self.btn4.clicked.connect(self.cb_get)
self.cb = QComboBox(self)
self.cb.move(btnposx+120,btnposy+150)
self.cb.resize(80,22)
self.cb.setMaximumSize(QSize(80,1000000))
self.cb.addItem('A')
self.cb.addItem('B')
self.cb.addItem('C')
self.cb.addItem('D')
self.cb.addItem('E')
self.show()
@pyqtSlot()
def cb_get(self):
global s
cbtext = str(self.cb.currentText())
s = cbtext
print(s)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())
This code shows a PyQt4 Widget. Function cb_get acquires the Value of a QcomboBox and can be used within the class App(). The Value is saved to variable s. How do I use variable s globally?
The only way I seem to get it to work is to write a new function for s and execute it on button click:
import sys
from PyQt4.QtGui import QApplication, QMainWindow, QPushButton, QLineEdit, QLabel, QComboBox, QProgressBar, QFileDialog
from PyQt4.QtCore import QSize, pyqtSlot
class App(QMainWindow):
def __init__(self):
super(App, self).__init__()
self.setGeometry(500, 300, 820, 350)
self.setWindowTitle("Widget")
self.initUI()
def initUI(self):
#Buttons
btnposx = 30
btnposy = 50
self.btn4 = QPushButton('GetValue', self)
self.btn4.move(btnposx,btnposy+220)
self.btn4.clicked.connect(self.cb_get)
self.btn4.clicked.connect(self.p)
self.cb = QComboBox(self)
self.cb.move(btnposx+120,btnposy+150)
self.cb.resize(80,22)
self.cb.setMaximumSize(QSize(80,1000000))
self.cb.addItem('A')
self.cb.addItem('B')
self.cb.addItem('C')
self.cb.addItem('D')
self.cb.addItem('E')
self.show()
@pyqtSlot()
def cb_get(self):
global s
s = str(self.cb.currentText())
def p(self):
print(s)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())
Well, at least now it has ist own function and I can write code for it seperately.
def initUI(self):
#Buttons
btnposx = 30
btnposy = 50
self.btn4 = QPushButton('GetValue', self)
self.btn4.move(btnposx,btnposy+220)
self.btn4.clicked.connect(self.cb_get)
self.cb = QComboBox(self)
self.cb.move(btnposx+120,btnposy+150)
self.cb.resize(80,22)
self.cb.setMaximumSize(QSize(80,1000000))
self.cb.addItem('A')
self.cb.addItem('B')
self.cb.addItem('C')
self.cb.addItem('D')
self.cb.addItem('E')
self.s = None # initialize it here so you don't have to use global
self.show()
@pyqtSlot()
def cb_get(self):
cbtext = str(self.cb.currentText())
self.s = cbtext
def get_s(self):
return self.s
and
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
# print(ex.get_s) # this won't work since you have to click on btn4 first
sys.exit(app.exec_())
